"separation between font- and backend": "font" instead of "front". "(an UNICODE or index)": "an" instead of "a". (U is a vowel, but its pronounciation starts with a consonant sound. The pronounciation decides whether a(n).) "A node can have a subtype to that it": "to" instead of "so". "with an node": "an" instead of "a". "(here we do that with [a]": Missing closing parenthesis. "but if you need a dozen you might wonder what you’re doing. .": Two consecutive full stops. "and expands it content": "it" instead of "its". "But this kind of expansion it still": Superflous "it". "This primitives is like \ignorespaces": "primitives" instead of "primitive". "These commands are use as": "use" instead of "used". "There is an nice side effect": "an" instead of "a". "in several places where the engine to deal with the dimensions of nodes": Missing verb. "as mentioned ,their": Space and comma transposed. "reference to an image s specification": Space instead of "'". "An implementation probably should accepts": "accepts" instead of "accept". "when no proper nested grouping is used": "proper" instead of "properly". "This is conform the LuaTeX philosophy.": "is conform" instead of e.g. "is conform to" or "conforms to". "can be present in en entry": "en" instead of "an". In section 6.2 (Defining Fonts) the word 'hash' is used strangely. It seems like it is used to mean hash tables: "The parameters is a hash with mixed key types", "The characters table is a list of character hashes indexed by an integer number", "Each character hash itself is a hash", "The kerns table is a hash indexed by character index", "The ligatures table is a hash indexed by character index", "with the values being yet another small hash, with two fields". "They were mostly use for": "use" instead of "used". "At the font level there can be a fonts an (indexed) Lua table."